This invention relates to an asphalt-containing composition suitable for use in preparing an asphalt-extended polyurethane surface. More particularly, it relates to (1) a method for stabilizing a polymerizable mixture comprising a high molecular weight diol component, a low molecular weight chain stiffener component and an asphalt component, (2) the resulting composition, and (3) a process for preparing said surface using the stabilized mixture.
Polymerizable asphalt-extended mixtures, commonly called premixes, are known in the polyurethane art (see for example U.S. Pat. Nos. 3,896,421; 3,900,687; 4,025,683; and 4,036,797). They are used for the preparation of asphalt-extended polyurethane surfaces for bridge decks, industrial membranes, recreational surfaces, such as running tracks, tennis court surfaces and the like, canal or pond linings, liquid surface coverings as in tanks, ponds and the like, road surface elements and the like, to name but a number of representatives. In the preparation, polyisocyanate, usually aryl diisocyanate, is thoroughly admixed into the premix and the resulting polymerizable or polymerizing mixture is applied or used as desired. The resulting product is an asphalt-extended polyurethane surface.
However, a premix frequently suffers from a serious disadvantage. That is, while initially it may be formuated by thorough mixing into a solution or apparently homogeneous substance, for example a dispersion, upon standing two or more separate phases develop. In separated form, the mixture has little or no value as a premix. It is said to have an unsatisfactory shelf life. Thus, there is a need for an improved premix composition which is fully stabilized against phase separations or at least stabilized to such an extent as to exhibit an improved and satisfactory shelf life.
This invention is directed toward (1) a method for stabilizing a premix, (2) the composition resulting from (1) and (3) a process for preparing an asphalt-extended polyurethane surface using the composition of (2).